Combined radio receiver equipment



'June2 3,1936. H. LICHTE ETAL v 2,045,276

COMBINED RADIO RECEIVER EQUIPMENT Filed-April l, l952 2 Sheets-Sheet l O 26 a 27 2a 29 30 INVENTOR HUGO LICHTE MARTIN ZEH PAU? GLASS KA SCHWARZ l I M ATTdRNEY Patented June 23, 1936 v UNITED STATES PATENT OFFICE 2,045,276 COMBINED RADIO RECEIVER EQUIPMENT Application April 1, 1932, Serial No. 602,454 In Germany April 1, 1931 2 Claims.

The invention is concerned with outfits which consist of a talking machine with electric soundbox and a radio set so designed as to utilize the equipment at will for radio or phonograph reproduction. The more particular object of the invention is to associate theconstituent parts of such an outfit (i. e., phonograph with soundbox, broadcast receiving set and loudspeaker) in the simplest possible manner by means of a changeover switch so that the equipment will be suited also for acoustic recording, and that the selective setting of the various modes of operation that are feasible, at least in major part, is possible by .the agency of one manipulating knob without existent equipment having to be rebuilt or to be provided with accessory or additional parts.

In case, for acoustic recording, the loudspeaker ;is to be used as the sound pick-up instrument \(microphone) the following modes of operation may be considered, to wit:

(a) Reproduction of broadcast transmission by means of loudspeakers.

(b) Reproduction of phonograph records (factory-made for instance).

-;(c) Recording of the voice or music produced in 'situ, on record disks.

(d) Reproduction of such disks recorded by the equipment.

(e) Recording of radio transmissions or programs, optionally with simultaneous audition thereof.

(1) Reproduction of voice or music produced at the place of installation (announcing or the like).

In order that these various problems may be properly solved switching or change-over means, according to the invention, are contained in a small box having the form of an accessory to the equipment, said box having inside or outside thereof terminals for the soundbox connections of the receiver (which represent the input circuit of the amplifier), for the output terminals of the receiver and for the loudspeaker. In other words, existing equipment need not be provided with additional terminals.

Arrangements according to this invention are furthermore so chosen that a further use (9) of the equipment may be found, namely, for dictaphone work. For this purpose, as will be understood, it is often desirable that the dictating person should talk only in a very low voice in order to preclude the risks of unauthorized persons listening in. Another point is that the pick-up microphone may be mounted in the neighborhood of the speaker or dictator with greater convenience than a loudspeaker, say, upon the desk, the loudspeaker, as to the rest, being customarily employed preferably only for entertainment. Hence, according to the invention the equipment may be provided with a microphone which at the same time may be connected for acoustic recording by action of the change-over device. For reproducing records, it may then be suitable to use a telephone instead of a loudspeaker.

The equipment could also be used for the recording of disks which'im'mediately or at some later time are to be rendered by the same equipment, or else for the recording of disks to be used for mailing communications instead of letters or postal cards, the contents of such acoustic records being made perceivable (read) at the addressees end by a similar equipment.

As such disks there may be primarily considered those of the kind adapted to receive a record by the intermediary of a soundbox (normally intended for reproduction), in such a way that they may be readily used for reproduction without further treatment.

For the recording of radio transmissions the acoustic vibrations when actually being recorded may be rendered audible simultaneously (sort of monitoring device). 0

An equipment as here disclosed in this respect will be found particularly suited for radio intelligence services, principally also for miiltary purposes, seeing that it is often diflicult, especially when the reception of intelligence in a foreign language is involved, to immediately read or comprehend the communication (including telegraphic code signals) in such a clear way that errors are precluded.

An equipment is here disclosed which could further be utilized for sound-film recording and in conjunction with a camera for the recording of both sounds and pictures for home cinematographic equipment, and also for the rendition of such sound and pictorial films (in combination with domestic projector machines).

All working potentials required for the operation of the entire equipment are derived from a supply-line or, in case of alternating current, from the rectified network potential of the radio set.

ferring to Fig. 1, ll denotes an electric pick-up or soundbox having a form of construction as well-known from the reproduction of phonograph records. The winding of the pick-up has terminals as indicated at 2|. l9 designates a radio set comprising radio frequency amplifier tube 27, a tube 28 for rectification, and two tubes 29 and 30 for audio frequency amplification (in two stages). The receiver |9 shall be assumed to be designed for selective reproduction of radio programs or phonograph records. For this purpose, in addition to the sockets or receptacles 24 for the connection of the loudspeaker l8, it has sockets 23 for the connection of the pick-up II.

In case of phonograph record reproduction, the tubes 28, 29, and 30 may be used, for instance, for amplification. The receiver shall be supposed to be designed, as known, in such a manner that in case of introduction of the plugs of the pick-up into the terminal sockets 23, the radio frequency amplifier stage is rendered inoperative, in other words, the broadcast reception is discontinued. For phonograph record reproduction the arrangement comprising the tubes 28, 29, and 30 constitutes an audio frequency amplifier with input terminals 23 and output terminals 24. These terminals or sockets, for the sake of better understanding, shall be designated by E and A, respectively, also the plug pins or line ends starting :therefrom. In a. similar way the connections or plugs of the pick-up or soundbox and of the loudspeaker shall be designated by P and L, respectively. The wires corresponding to the terminals P, L, E, and A are indicated at 35, 3B, 31, and 28 respectively. In order that the equipment may be changed over to adapt it to phonographic record reproduction it is necessary to plug in P atE.

Now, according to the invention an accessory device 4| is provided which has terminals or sockets L, P, A, E, for loudspeaker, pick-up, output and input of receiver, and which also comprises a change-over or switching device so that, preferably by the aid of a single operating knob the microphone employed as the pick-up instrument,

the microphone with the casing 26 is provided.

25 designates terminals or sockets at which the 1 alternating current potentials furnished from the microphone and corresponding to the acoustic I vibrations are collected by way of leads 40. The

sockets 25 or the connections associated therewith shall be denoted simply by M in what follows. For feeding the microphone a battery 48 of the pocket-lamp type is accommodated inside housing 26.

The terminal sockets L, P, A, E, M, in the V embodiment here shown, and as illustrated in Fig.

2, are accommodated at the lid surface 42 of the accessory box 4|. In the schematic illustration Fig. '1, the frame 42 corresponds to the lid or cover plate 42. The change-over device, for instance, is mounted upon the base plate 43 of the casing 4|. The same is illustrated schematically in Fig. 1. The frame 4| (there shown by dashlines) corresponds to the base plate 43 (Fig. 2). The change-over device comprises two spring packet assemblies I and II, each thereof consisting of two packets. The constituent springs are united with the sockets L, P, A, E, and M in a way as shown. The switch lever or arm 45 pivotable about the axis 44 is designed to occupy three positions 3|, 32, and 33.

In the position 3| as shown, the equipment is connected for the reproduction of phonograph records, in other Words, the input (E) of the amplifier is connected with the phonograph pickup device (P), and the output end (A) of the amplifier with the loudspeaker (L), the former connection being established by Way of the contacts I3 and 9, and 4, respectively, and the latter by way of the contacts 6 and H, and I5, respectively.

When the switch arm 45 is in position 32, the equipment i adapted to operate for acoustic recording by the use of the loudspeaker to act as a microphone or pick-up instrument. The input (E) of the amplifier therefore is united by way of contacts IS and I2 with the loudspeaker (L), and the output (A) of the amplifier by way of contacts 6, l0, 4, and M, respectively, with the soundbox or pick-up (P).

In position 33 of the switch lever 45 the outfit is arranged for acoustic recording by the aid of the microphone 46 housed in box 25. In this case the input (E) of the amplifier is associated by Way of contacts 5 and with the output terminals 25 of the microphone, the output circuit (A) of the amplifier by way of the contacts with the soundbox M.

In position 3| of the switch lever 45, record I disks impressed with recording by the loudspeaker or microphone may be reproduced. The connection by the aid of the spring contacts is so effected that the circuits of the various modes of operation are blocked similarly in reference to one another. The switch lever 45 is disposed so as to be moved in a cut-out (slot) 41 on the anterior face of the small box 4|.

Modern receiver sets mostly are designed for being supplied with energy from a supply-line or network. When using a battery for feeding the microphone this battery from time to time must be replaced by a fresh one. Hence, according to another object of this invention, to obviate the necessity of substitution, also the microphone is fed from the network or is supplied with rectified network current as used for the feeding of the receiver set. For this purpose two terminal sockets 49 (Figs. 3 and 4) are provided on the little box 26. The circuit scheme preferably to be used because of its simplicity is indicated schematically in Fig. 3. The microphone 46 in series with a resistance 50 is connected with network potential source 49, the value of this potential, fundamentally speaking, being too high for the microphone. The said resistance is so chosen that the microphone is supplied with the desirable mean working current, say, of 5 milliamperes. If the network potential is 110 V. the said resistance must then have a size of about 20,000 ohms. Suitably by way of condensers 5|, 52 the alternating current potentials are taken off, optionally by way of a shiftable contact or slide, and thus fed to the connection means 25. Resistance and microphone are suitably so disposed that the microphone is at ground potential.

In some instances it may be of advantage to accommodate the small box 26 and the parts contained therein with (inside) the small box 43 of the change-over means. Inside the same also other parts could be housed, chiefly parts that are needed for coupling or adapting the soundbox, the loudspeaker or the microphone to the 7 input 'or output circuit of the amplifier.

Fig; 5 shows that the casing 4| contains a condenser 54 and a choke-coil 53. The said condenser 54 is connected in series with a supplylead of the soundbox, and the choke-coil 53 is in parallel relation to the two leads of the soundbox. At P (Fig. 5), the connecting plug of the soundbox is introduced similarly as in Fig. 2. The springs required therefor in the change-over device must then be connected at 55 and 56.

As already pointed out when using the equipment for dictaphone work one may utilize a sensitive microphone to act as the pick-up device since such an instrument may be readily mounted upon the writing desk, and since the dictating person needs to talk only in a low voice thus practically precluding the risk of unauthorized persons listening in. The box 26 therefore generally speaking will preferably be placed upon the desk. For this purpose the use of a stand with frame may be provided in which the small box is suspended.

Now, so far as the dictating person is concerned it is of substantial advantage to be enabled to reproduce the dictation at any desired instant by means of a telephone or head-set. For if the loudspeaker were to be used for this purpose the danger of listening-in by others would be present again. Hence, according to another object of this invention, in conjunction with the microphone 46 and box a telephone or headset T is provided. Its connector plugs are adapted to be inserted in the sockets 26 whence a pair of conductors 30 is brought to the box 4|.

The said leads 39 terminate at the pair of plugs 51 (Fig. 1) which instead of the plug of the supply lead 36 of the loudspeaker may be introduced into sockets designated by L in the box 4|. In the position 33 of the switch lever 45 acoustic recording is insured by the aid of the microphone 46, in the position 3| reproduction of acoustic record (disks) by means of the telephones T.

If radio programs or communications are to be received by the aid of the equipment all that is necessary is to withdraw the plugs of the leads 31 from the sockets 23 (E) of the receiver and to throw the switch device over to reproduction (position 3|, Fig. 1) for in that case the output end of the amplifier is associated with the loudspeaker.

Also the recording of radio programs is feasible quite simply. In fact, all that is necessary, supposing that the equipment is set as last described, to throw the lever 45 into the position 32. The output circuit of the amplifier is then connected with the soundbox. The connection of the loudspeaker with the input end of the amplifier is then interrupted inasmuch as the plug 31 is withdrawn at 23. Now, in recording radio reception it is desirable that the incoming program should be heard at the same time. For this purpose, on the cover plate 42 of the box 4|, in addition to the terminal sockets L, P, A, E, and M beforementioned, there are provided two sockets LK which are united with the sockets A (Fig. 6). When the outfit is set to receive radio programs it is feasible to hear by means of the loudspeaker L or headphone T plugged in at LK what is being recorded at the same time.

It has already been pointed out that the parts which are housed inside the box 20 might be accommodated with the box 4| of the change-over device. The parts accommodated inside the box 4!, in turn, could be disposed either within the box of the disk player (phonograph) or the radio set, if desired, conjointly with the parts of the box 29.

However, in connection with the use of the equipment for dictaphone work it is generally suitable to arrange the parts of the box 20 separately, either, as shown, inside a box 20 or else in the form of a telephone instrument customary in telephone services (microphone and receiver). r

In these latter cases the resistance 50, the condenser EI and 52, and the necessary binding posts or sockets are most conveniently arranged inside the box 4| or in the radio set (or else inside the phonograph) so that the telephone instrument contains only the microphone and the receiver. Between these and the other parts of the outfit the requisite electrical connections are established by means of a 'multi-conductor cable or cord.

The change-over or switch device may be designed in widely varying ways so as to adapt the same to insure the most different switching operations in order that the changing of plugs of any kind for changing the circuit conditions of the equipment can be made entirely dispensable. In fact, for this purpose a dial switch of automatic action may be used of the kind as employed in automatic telephony. By increasing the number of springs or the contacts borne thereby in spring packet means of the kind here indicated, it is possible to increase the number of possible switching operations in the most simple manner.

In simpler and less expensive equipment, the plugging and replugging of connectors may be acceptable in part. An equipment designed to insure sound impression by the aid of a loudspeaker used in lieu of the pick-up microphone may be sound-impressed by a real carbon microphone by switching the equipment over for acoustic recording, the plug of the loudspeaker being then withdrawn, while the sockets are fed with the voice currents furnished from a carbonmicrophone, for instance.

The soundbox may be of a type serviceable both for sound reproduction as well as for sound recording. The disks preferably to be employed are of the kind in which the recording can be used for reproduction without any further treatment or preparation; for the point is to have the disks ready for reproduction immediately after the recording work has been completed or to mail them in lieu of a letter immediately after the recording so as to enable the addressee to read the message with the aid of a phonograph machine and a radio set without any incidental difliculties. Such record disks should be impressable by the acoustic vibrations without any distortion and should be similarly adapted to reproduce the recording; other desiderata are that they should be of very low weight and fire-proof. Particularly suitable have been found in the experiments which led to the present invention record disks consisting of a thin, though sufliciently strong stiff disk of some low-weight material such as aluminum preferably, bearing a coating of bees wax, soap or the like.

What may also be mentioned is that in some instances it is of advantage to couple the changeover switching device of the equipment with the switch changing the wave-length ranges in such a way that both are operable by the aid of one and the same operating handle or knob.

The illustration in Fig. 7 shows in what way the space is utilized in an embodiment of the invention shown by way of example. In one room, upon a small table, there is mounted the disk-record phonograph, in its neighborhood upon a larger piece of furniture there is mounted the broadcast receiver comprising a loudspeaker. At

a slightly greater distance there is placed upon the writing desk the microphone, the single-piece receiver, and the small box which houses the change-over device and which is furnished with terminals for the microphone and telephone. The desired circuit changes are insured by the agency of the manipulating handle or knob disposed on the said box. For entertainment, preferably the loudspeaker is used for recording and as a pick-up device, while for business dictation or similar services, the microphone is employed. In this latter instance, in order to reproduce the recorded dictations, the single-piece telephone receiver may be employed in the most convenient way.

What is claimed is:

1. In combination with a radio receiver including a detector and audio amplifier, a loudspeaker, an electrical pick-up device, a microphone, a circuit connector box, connections from said pick-up, speaker and microphone to said connector, a connection between the amplifier output and said connector, an auxiliary connection from the said connector adapted to be connected to the detector input, and a single switch device connected to said connector, said switch being constructed to selectively connect the microphone or speaker in separate positions to the detector input and the pick-up to the amplifier output for recording, said switch additionally being arranged to connect in another position the pick-up to the detector input and said speaker to the amplifier output for reproducing records,

said switch device comprising a spring packet assembly.

2 In combination with a radio receiver including a detector and audio amplifier, a loudspeaker, an electrical pick-up device, a microphone, a circuit connector box, electrical connections from said pick-up, speaker and microphone to said connector, a connection between the amplifier output and said connector, an auxiliary connection from the said connector adapted to be connected to the detector input, and a single switch device provided on said box connected to said connector, said box being portable whereby it may be moved from place to place while said electrical connections remain intact, said switch being constructed to selectively connect the microphone or speaker in separate positions to the de tector input and the pick-up to the amplifier output for recording, said switch additionally being arranged to connect in another position the pick-up to the detector input and said speaker to the amplifier output for reproducing records, said switch in one of said separate positions, when said auxiliary connection is disconnected from the detector input, connecting said pick-up to said amplifier output whereby radio broadcast programs may be recorded simultaneously with reproduction in said speaker.

PAUL GLASS. KARL SCHWARZ. HUGO LICHTE. MARTIN ZEH. 

